What are some signs a guy on tinder is looking for something more serious?

I know some people think tinder is just for hooking up but I know some poeple use it to date just like any other dating site and are not necessarily looking to just hook up. What would you say are some signs that a guy is not just looking to hookup on there? I've been talking to a guy on tinder for about three weeks. He seems sweet and has asked a lot of questions getting to know me. He doesn't give me the impression he's looking just for sex but who knows. What are some signs to watch out for that says a guy just wants to hookup on tinder?